is available from the above paper's links to the author's Zenodo page:

https://doi.org/10.5281/zenodo.82994949

and github repository:

https://github.com/gscheler/GNN/tree/v0.1

and also in this ModelDB entry (downloaded from Zenodo 20190517).

Usage: Download and extract the GNN-v0.1.zip ezyfit2.45.zip from the above links which will create the ezfit and gscheler-GNN-40349ef folders (provided in this ModelDB entry). Start matlab and add these two folders to your matlab path. sim_G_adj and sim_W_adj can be run on the command line and generate distributions of weights in 80 interations each.